Local authorities can establish specifications for outdoor lighting and infrastructure lighting including standards for lighting fixtures and requirements for light levels.
6.1 Traffic Lights
The availability of compact LED packages on the market boosts the replacement of incandescent lamps in traffic lights with more energy-efficient and durable LED (42) ones.
This action yields a significant reduction of energy consumption. A LED array is composed by many LED unities. The main advantages of LED traffic lights are:
The light emitted is brighter than the incandescent lamps, which make LED traffic lights more visible in adverse conditions.
A LED's lifespan is 100 000 hours (about 10 times more than incandescent bulbs).
This implies a significant reduction of maintenance costs.
The energy consumption reduction is higher than 50 % with respect to incandescent bulbs.
Box 14. LED Traffic lights: Verona, Italy
The action consists in a complete replacement of the incandescent lanterns of traffic lights with LED lanterns, in order to reduce the maintenance costs, the electricity consumption and, hence, carbon emissions. The energy and economic savings amount to 75 - 80% for electricity consumption (Electricity savings 1036 MWh / year) and the carbon emissions avoided to 513 tCO2 / year.
In particular, the number of lanterns is 1885, with 80 W lamps and an average daily operation of 21 hours, for a total estimated consumption of 613.2kWh/year per lantern. The overall consumption of the incandescent lanterns at present is 1155882 kWh / year (1885 x 613.2).
Assuming a total replacement with LED lamps that show an average power of 8.3 W and a total consumption of 119.9 MWh / year, the saving achievable is 1035.98 MWh /year (1155.88 - 119.9).
Moreover, since the costs of LED lanterns have drastically decreased in the recent years, the payback time is short (two / three years) thanks to energy savings of about 80%.
The overall replacement will be carried out by 2020. The action brings several co-benefits: a reduction of maintenance costs and consumables, improved brightness even in critical atmospheric conditions and road safety.
http://www.covenantofmayors.eu/about/covenant-community/signatories/key- actions.html?scity_id=1843
6.2 Public lighting
Public lighting is an essential municipal service. It offers significant potential for energy efficiency (43), in particular through the replacement of old lamps with more efficient ones, such as low pressure, high pressure lamps or LED. Over the years the efficiency of lamps has improved significantly. The high-pressure mercury lamp is the most frequent in public lighting. It has been used since 1960s and is extremely energy in-efficient.
High-pressure sodium and Metal Halide lamps are very energy efficient ones and commonly used recently.
Replacing lamps is the most effective way to reduce energy consumption. However, some improvements, such as the use of more efficient ballast or adequate control techniques, are also suitable measures to avoid the excess of electricity consumption. In addition, the use of autonomous public solar street lighting systems powered by PV panels with energy storage battery is spreading across cities.
(42) LED – Light Emission Diode
(43) Further information available at www.eu-greenlight.org and www.e-streetlight.com (European project supported by Intelligent Energy Europe)
Luminous efficiency, CRI, duration, regulation or Life Cycle must be included in the set or design parameters for the choice of the most suitable technology. For instance, if a high CRI is required in a public-lighting project, the use of LED technology is recommended.
This technology is a suitable solution to reach a good balance between CRI and Luminous efficiency. If CRI is not essential for a given installation, other technologies may be more appropriate. In the following Table 18, recommended lamps for public lighting are reported in case of either replacement or new installation.
Table 18. Recommended ended Lamps Direct substitution and new installation Type of
intervention Original Lamp Luminous
efficiency Recommended lamp Luminous efficiency
Direct substitution
High pressure mercury lamps Arc lamps
32-60 lm/W 30-50 lm/W
Standard high
pressure sodium lamp 65-150 lm/W Metal Halide Lamp 62-120 lm/W
LED 65-100 lm/W
New Lighting Installation
Less than 60
Low pressure sodium
lamp 100-200 lm/W
Standard high
pressure sodium 65-150 lm/W
More than 60 LED 65-100 lm/W
Arc discharge lamps, such as fluorescent and HID (High Intensity Discharge) sources, require a device to provide the proper voltage to establish the arc and regulating the electric current once the arc is struck.
Box 15.
I) Exchange of sodium lamps for LED streetlights: Ostrava, Czech Republic Ostrava decided to modernise public lighting in the period of 2010 – 2013. The number of lighting points increased as well as the energy performance. In accordance with the Sustainable Energy Action Plan modernization of public lighting system continued, including use of LED technology and renovation of lightning points, which replaced the previously commonly installed lamps. LED lamps with built-in control are used from 2014 with a systematic renovation of lighting points.
http://www.covenantofmayors.eu/plans-and-actions/good-practices.html
II) Installation of solar street lighting: Gradiška, Bosnia and Herzegovina
Gradiška provided the installation of solar public lighting with PV panels for the production of electricity for 72 street lamps installed in the main street of the city. The power of the mini power plant with PV is 14.5 KW and it produced 18345 MWh/y. The installation takes place by 2020.
http://www.covenantofmayors.eu/plans-and-actions/good-practices.html
Other measures may be implemented to achieve significant energy reduction:
Take into consideration the use of the public area (parking, pedestrian, dangerous intersection) in order to provide the appropriate kind of lamp and level of lighting.
Ballasts: compensate voltage variation in the electrical supply. Since the electronic ballast does not use coils and electromagnetic fields, it can work more efficiently than a magnetic one. These devices allow a better power and light intensity control on the lamps. The energy consumption reduction caused by electronic ballasts has been
estimated around 7% (44). In addition, LED technology not only reduces the energy consumption, but also allows an accurate regulation depending on the needs.
Electronic photo-switches can contribute to the electricity savings in public lighting by reducing night burning hours (turning on later and turning off earlier).
A tele management system enables the lighting system to automatically react to external parameters like traffic density, remaining daylight level, road constructions, accidents or weather circumstances. Even if a tele management system does not reduce the energy consumption in lighting by itself, it can reduce traffic congestion or detect abnormalities. Tele management systems can be used to monitor failed lamps and report their location. Maintenance expenses can be reduced by considering the remaining life of nearby lamps that might be replaced during the same service call.
Finally, data collected by the tele management system that tracks the hours of illumination for each lamp can be used to claim warranty replacement, establish unbiased products and supplier selection criteria, and validate energy bills.
(44) E-street project www.e-streetlight.com. Supported by Intelligent Energy Europe